<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<style>
    div{
        width: 100%;
        height: 100px;
        border: 2px solid red;
    }
    .div1{
        position:relative;
        top:300px;
        left:300px;
    }
    .div2{
        position: fixed;
        top: 500px;

    }
</style>
<body>
    <div    class="div1">第一个标签</div>
    <div    class="div2">第二个标签</div>
    <div    class="div3">第三个标签</div>
</body>
</html>